In this paper I will try to semantically analyze the subject matter of First Philosophy, i.e. ‘t? ??’. In doing so, I rely on Charles Kahn’s works. ‘t? ??’ in Greek thought mainly refers to what is accessible. This is what mystics mean by “that which is”. To make this clear, I will discuss the Persian equivalent of this Greek word. Then, with reference to Arabic translations of Metaphysics and the equivalents of ‘t? ???al’, ‘t? ??’, and ‘t? ??t??’ in these texts, I will semantically analyze those equivalents among which Mawj?d is the most prominent. I will show the background of this word in the Arabic language and especially in The Translation Movement. Finally, I will explain the semantic relation between Mawj?d and its Greek equivalent.